Starrett KA19 Hole Enlargement Arbor For A1, A2 & A10 The A19 \'Oops\' Arbor is for use in conjunction with either the A1, A2 or A10 type hole saw arbors (e.g. A1-1, XA2, A1E etc). Replacing the pilot drill, the \'Oops\' Arbor allows diameters to be enlarged by attaching a saw of the same size to that of the existing hole, thereby acting as a pilot for the larger diameter saw. Minimum hole enlargement is 4.7mm (3/16\") between the pilot saw diameter and the cutting saw diameter. The A19 ‘Oops’ Arbor works with the following holesaws because they all have the same screw threads (1/2”-20 & 5/8”-18): (SH) Constant Pitch HSS Bi Metal Holesaws (DH) Dual Pitch HSS Bi Metal Holesaws (MPH) TCT Multi Purpose Holesaws (CT) Carbide Tipped Holesaws (D) Diamond Grit Holesaws FEATURES Use with the A1, A2 or A10 type hole saw arbors Replaces the pilot drill bit Allows diameters to be enlarged by attaching a saw of the same size to that of the existing hold, therefore acting as a pilot for the larger diameter saw Minimum hole enlargment is 4.7mm Works with a wide range of Starrett hole saws SPECIFICATION Pack Quantity: x1 Pc Part No: A19